gistfile1.js

ContactSchema.pre('save', function(next) {
    var self = this;
    Step(
        function count() {
            Message
                .find({author: self.user, recipient: self.contact})
                .count(this.parallel());
            Message
                .find({author: self.contact, recipient: self.user})
                .count(this.parallel());
        },
        function saveCount(err, count_1, count_2) {
            if(err) {
                return next(new exception.Fatal(err));
            } else {
                self.count = count_1 + count_2;
                self.save(next);
            }
        }                                                                                                                                                                         
    );
});